Condensate purification process

ABSTRACT

A process for treatment of power plant condensate water particularly from a boiling water nuclear reactor, where the condensate contains colloidal material, especially oxidized iron from the steam and condensate handling system known as &#34;crud&#34;. The colloidal iron level of the condensate is lowered by contacting the condensate water with a mixed bed ion exchange resin in which at least the cation exchange resin has a core/shell morphology which has been prepared by a polymerization of monomer within a multiplicity of free radical-containing matrices.

BACKGROUND OF THE INVENTION

The invention pertains to the purification of power plant condensatewater. In nuclear power plants and in conventional fossil fuel plants,it is desired to maintain the level of dissolved and suspended speciesin the steam loop at a minimum to avoid corrosion. In a boiling waternuclear reactor (BWR), it is especially desirable to maintain the waterin the steam loop as pure as possible because the impurities in thatloop are subjected to irradiation when passing through the "hot" side ofthe loop. This causes such impurities in many cases to themselves becomeradioactive species, which must then be handled and ultimately disposedof in a safe manner when it is necessary to clean the steam loop.Furthermore, accumulation of suspended solids may cause pressure buildup in the system, reducing flow rate and lessening the efficiency of thepower plant operation. Consequently, the lower the level of impurities,especially suspended solids, that can be maintained in the steam loopthe better.

Japanese Kokai publication 1-174998 (1989) proposes the removal ofsuspended impurities from the primary coolant of a boiling water nuclearpower reactor by use of mixed bed ion exchange resins having lowcrosslinker (divinylbenzene) content of 3-7.5 percent. The publicationtheorizes that lower cross-linked resins have larger micropores and arerelatively soft and more elastic than ion exchange resins having ahigher level of cross-linkage and that these properties permit the lowercross-linked resins to more effectively remove the "crud" fromcondensate water.

In Japanese Kokai publication 63-59355 (1988) it is noted from anEnglish abstract of same that a cation exchange resin was oxidized in adilute sodium sulfate solution using platinum electrodes with a 2 amperecurrent for 3 to 4 hours. The oxidized resin is said to be useful forremoval of fine, amorphous particles in condensate water, whichparticles are produced from corrosion of the piping and other materialsof construction in thermal or nuclear power plants.

In U.S. Pat. No. 4,564,644 are described shell/core morphology ionexchange resins. They are of the same structure as those utilized in thepresent process. They are said at column 13, lines 3-12, to be usefulunder harsher conditions than prior gel-type resins and in particularfor condensate polishing and in mining operations. However, theirspecial ability to remove colloidal iron to a previously unattainabledegree is not suggested nor is any special utility for BWR condensatecrud removal mentioned.

SUMMARY OF THE INVENTION

The invention is a process for the reduction of colloidal iron in powerplant condensate water. More particularly, it is a process for treatmentof BWR condensate water to reduce the colloidal iron to levels which,over an extended time, are significantly lower than obtained when usingconventional gel-type ion exchange resins in the same process.

With the invention process, sustained removal of about 95 percent ofcolloidal iron is attained, compared to sustained removal of only about75-80 percent in processes utilizing conventional ion exchange resins inmixed beds.

The invention process comprises contacting BWR condensate water whichcontains colloidal iron with a mixed bed ion exchanger and thereafterdecontacting the water, now having a reduced colloidal iron content,from the ion exchanger, wherein the mixed bed ion exchanger comprises:

Component (1)--a particulate cation exchange resin, at least a p ortionof which is in the acid form, and

Component (2)--a particulate anion exchange resin, wherein at least theComponent (1) resin, and preferably also the Component (2) resin, priorto functionalization as hereinafter defined, primarily comprisesgel-type copolymer beads having core and shell structure, which beadshave been produced in stages by first forming in a continuous phase amultiplicity of polymermatrices which contain free radicals, thenimbibing in said matrices a monomer feed comprising at least one monomerbut no free radical initiator and subjecting the imbibed monomer feed toconditions such that the free radicals in the matrices catalyzepolymerization of the monomer feed within the matrices.

Preferably, the copolymer beads employed in Component (1) or (2), andmore preferably both, comprise beads of copolymers prepared at leastpartially from a monovinylidene aromatic monomer and a divinylidenearomatic monomer. Especially preferred are copolymer beads comprised ofcopolymers prepared at least partially from styrene and.[.divinylbenze.]. .Iadd.divinylbenzene .Iaddend.(DVB). Most preferably,the copolymer beads utilized in the invention process are preparedentirely from monovinylidene aromatic monomer and a divinylidenearomatic monomer; more preferably, entirely from styrene and DVB.

Preferably, the functionalized copolymer beads of Component (1) employedin the invention process have crush strengths, as defined hereinafter,of at least about 700 g/bead, more preferably at least about 800 g/bead.Preferably, the functionalized copolymer beads of Component (2) havecrush strengths of at least about 500 g/bead, more preferably at leastabout 600 g/bead.

Preferably, the functionalized copolymer beads of Components (1) and (2)have osmotic shock resistance of a magnitude such that less than 15percent and more preferably less than 10 percent, .[.by number of thebeads.]. .Iadd.are broken after .Iaddend.contact with 10 cycles ofalternating 8 molar hydrochloric acid and 8 molar sodium hydroxide,where contact with both the acid and the base constitutes one cycle.

Preferably in the invention process, Component (1) has, prior to contactwith the condensate water, been converted primarily to the acid form,e.g. by contact with a strong acid such as sulfuric acid. Likewise,Component (2) preferably has been converted primarily to the hydroxylform prior to contact with the condensate water, for example, bycontacting Component (2) with a strong base such as sodium hydroxide, ifit is not already in that form.

Components (1) and (2) typically are present in the (1):(2) volume ratioof from about 3:1 to about 0.5:1, and preferably from about 2:1 to about1:1.

In a particularly preferred mode, the gel-type copolymer beads which arethe source of the Component (1) or (2) resins in the ion exchanger, areprepared by:

(i) suspending a multiplicity of styrene-DVB copolymer seed particles offrom about 0.1 preferably from about 0.2, up to about 2.0, preferably upto about 1.0, percent DVB by weight, in a continuous aqueous phase, and

(ii) imbibing in those seed particles a monomer mixture of styrene, DVBand free radical initiator and then initiating the reaction of theimbibed styrene and DVB until at least about 20 percent, preferably atleast about 40 percent until about 85 percent, preferably up until about90 percent by weight of the initial monomer charge is converted topolymer in the particles, and then

(iii) continuing to add to the aqueous suspension a second monomercomposition which comprises styrene and DVB but essentially no freeradical initiator, under conditions so that the second monomercomposition is imbibed in the particles and polymerization of the secondmonomer composition is catalyzed within said particles.

The foregoing polymerization is then suitably continued untilessentially all of the first monomer mixture and the second monomercomposition are polymerized. Preferably, the first monomer mixturecomprises from about 1, more preferably from about 2, up to about 10,more preferably to about 8 weight percent divinylbenzene. Alsopreferably, the second monomer composition comprises from about 90, morepreferably from about 95, up to about 98, more preferably to about 100weight percent styrene.

The condensate water treated by the invention process is condensate froma boiling water nuclear reactor. Also, the condensate water is suitablypassed through a mechanical filter, such as a standard porous filter orother similar means to remove larger size particles of suspended solids.Preferably, however, the process is conducted without the use of apretreatment such as the mechanical filtration, because the extremelyeffective action of the mixed bed resins used in the invention processrenders this unnecessary or at least reduces the size of the filtrationunit that need be employed.

DETAILED DESCRIPTION OF THE INVENTION

The process of this invention depends upon the utilization of ionexchange resin beads of a very particular morphology, which is referredto as "core and shell structure", as defined hereinafter. They arecharacterized by having high crush strength and resistance to osmoticshock when converted to ion exchange resins. The copolymer beads arefunctionalized to form strong acid, weak acid, strong base, or weak baseion exchange resins, all of which compared to typical gel-type resinswill exhibit improved mechanical properties. Preferably, only strongacid and strong base ion exchange resins are used in the inventionprocess. Representative anionic or cationic groups are describedhereinafter. Said resins retain other desired characteristics ofgel-type resins, i.e. high capacity and good ion selectivity.

The term "core/shell morphology" as employed herein, means that thepolymeric structure of the copolymer beads used in this inventionchanges from the inside to the outside of the bead. Said changes inpolymeric structure may be somewhat gradual from the inside to theoutside of the bead, yielding a bead having a gradient of polymericstructure along any radius thereof. Alternatively, said changes inpolymeric structure may be relatively abrupt as one moves along a radiusof the bead outward from the center, yielding a bead having a relativelydistinct core with one polymeric structure and a second relativelydistinct shell with another polymeric structure. The rate of saidchanges in the polymeric structure of the bead is not particularlycritical. Accordingly, as used herein, the terms "core" and "shell"refer to the polymeric structure of the inside and the outside of thebead, respectively, and the use of said terms should not be construed asmeaning that the beads used will exhibit a distinct interface betweenthe polymers of the inside and the outside of the bead.

It is understood that in describing "core polymers" and "shell polymers"there is usually, if not always a significant amount of interpenetrationof the polymers residing in the core and shell of the copolymer beads.Thus, the "core polymers" will extend somewhat into the shell of thebead, and vice versa. The terms "core polymers" and "shell polymers" andlike terminology are employed herein to describe the polymeric materialin the named portion of the bead in a general way without attempting toidentify any particular polymers as "shell" or "core" polymers.

The aforementioned core/shell morphology of the copolymer beads isdetectable using various known techniques for determining the structureof polymeric materials. In general, one or more of the followinganalytical techniques, among others, can be suitably employed todetermine the core/shell morphology of the copolymer beads used in theinvention: dynamic thermal analysis, differential thermal analysis,osmium staining techniques, measurement of the respective refractiveindices of the core and shell of the copolymer beads, conventionaltransmission electron microscopy, analytical transmission electronmicroscopy, scan transmission electron microscopy, and other suitabletechniques. In addition, the beads of this invention often exhibitsymmetrical strain patterns which are detectable by examination of thebeads under polarized light. Often, the core/shell morphology of thecopolymer beads of this invention is discernible simply from a visualinspection of the beads at no or low magnification, wherein the core isseen as an area of different color or as a darker or lighter area thanthe shell.

When functionalized to form an ion exchange resin, the core/shellmorphology of these beads can often be seen by immersing a dry bead intowater and determining the rate at which the bead becomes hydrated.Typically, the penetration of the shell portion of these beads by wateris more rapid than the penetration of the core.

The beads preferably have a shell containing an average proportion ofcrosslinking monomers which is less than or equal to the averageproportion of crosslinking monomers in the core. Beads of this type willhave a shell which is softer (i.e. less friable and more elastic) thanthe core of the bead, thus allowing the bead to retain its shape andintegrity yet permitting the bead to distribute energy throughout itsstructure when subjected to external stresses and pressures. Bydistributing the energy throughout its structure, it is believed thatthe crush strength and resistance to osmotic shock of theseheterogeneous beads is greatly enhanced.

Alternatively, or in addition to the difference in the crosslinkdensities of the core and the shell, the polymers in the shelladvantageously have a higher molecular weight than the polymers of thecore. It is believed that said higher molecular weight of the shellpolymers imparts mechanical strength to the bead and increases itsresistance to osmotic shock.

The copolymer beads used herein generally exhibit an effective crosslinkdensity which is higher than the average proportion of the crosslinkingmonomers actually employed in the preparation of the core and the shell.The effective crosslink density is determined from the percent volumeincrease after swelling the beads with toluene by using a graph such asdepicted on page 879 of the Kirk-Othmer Encyclopedia of ChemicalTechnology, 2nd Edition, published in 1966 by John Wiley and Sons, Vol.II, R. M. Wheaton and A. H. Seamster, "Ion Exchange". In general, thebeads of this invention will exhibit an effective crosslink density ofabout 1.5 to about 5 times that predicted from the average proportion ofcross-linking monomers employed in the polymerization of the core andshell.

The copolymer beads used in this invention exhibit excellent crushstrength and, when converted to anion or cation exchange resins, exhibitexcellent resistance to osmotic shock. The crush strength of thecopolymer beads is excellent whether employed as an anion or cationexchange resin. However, the mechanical and osmotic properties of theresin vary somewhat according to the type and amount of active ionexchange groups contained thereon. Since the crush strength of acopolymer bead is generally lowest when fully aminated to form an anionexchange resin, the crush strengths of said fully aminated beads areused herein for the purposes of comparing the crush strengths ofcopolymer beads. By "fully aminated" is meant that at least 75,preferably at least 90, more preferably at least 95 percent of therepeating units in the bead to which amine groups can be attached bearamine groups. The degree of amination is often indicated from the ionexchange capacity of the aminated resin. Fully aminated gel-type ionexchange resins generally exhibit a dry weight capacity of at least 4.0meq/g, usually at least 4.2 meq/g, although it is noted the capacity canalso be influenced by other factors, such as the degree of crosslinking,the particular polymers present in the resins and the porosity of theresin.

"Crush strength," as that term is used herein, refers to the mechanicalload required to break individual resin beads, given as a number averageof about 30 testings. The crush strength of gel-type beads used hereinwhich have been fully aminated to form anion exchange resins is at leastabout 400 g/bead, preferably at least about 500 g/bead, more preferablyat least about 600 g/bead. By contrast, most previously used gel-typecopolymer beads, when fully aminated to form anion ion exchange resins,exhibit crush strengths of less than 500 g/bead. When sulfonated to formstrong acid-type cation exchange resins, the copolymer beads used in theinvention process generally exhibit crush strengths of at least about500 g/bead, preferably at least about 700 g/bead and more preferably atleast about 800 g/bead.

The functionalized beads (i.e., those to which active ion exchange siteshave been attached) used herein also exhibit excellent resistance toosmotic shock. Resistance to osmotic shock for the purposes of thisinvention is measured by subjecting a quantity of the functionalizedbeads to 10 cycles of alternate treatments with 8M hydrochloric acid and8M NaOH, wherein each treatment is separated by backwashings withdeionized water. One full cycle of said treatment comprises (a)immersing a quantity of beads into 8M acid for one minute, (b) washingwith deionized water until the wash water is neutral, (c) immersing thebeads in 8M caustic sode for one minute and (d) washing the beads withdeionized water until the wash water is neutral. All references toalternating treatments with 8M hydrochloric acid and 8M NaOH containedherein refer to repeating cycles of this test. The resistance to osmoticshock of the beads is measured by the number of beads which remainunbroken after 10 cycles of the test. Typically, at least 85 percent ofthe functionalized beads will remain unbroken after 10 .[.cyles.]..Iadd.cycles .Iaddend.of the osmotic shock test. Preferably, at least 90percent, more preferably at least 95 percent, of the functionalizedbeads will remain unbroken after 10 cycles of the osmotic shock test.

In addition, the ion exchange resins comprising copolymer beads having acore/shell morphology as described hereinbefore, when fully aminated orsulfonated, will exhibit ion exchange capacity comparable to those ofconventional gel-type resins. It is noted, however, that ion exchangeresins having somewhat lower ion exchange capacity can be prepared fromthe copolymer beads of this invention by intentionallyunderfunctionalizing the beads. However, the dry weight capacity of theanion exchange resins used in this invention will generally be at leastabout 2.5, preferably at least 3.5, more preferably at least 4.0 meq/s.Cation exchange resins used in this invention will generally exhibit adry weight capacity of at least 2.5, preferably at least 4.5, morepreferably at least 5.0 meq/g.

The copolymer beads used in this invention can be prepared in anysuitable size but advantageously have an average diameter in the rangefrom about 50 to 2000 microns, preferably from about 200 to 1200microns. Said beads are of the so-called "gel" or "microporous" type. Inaddition, the core of the beads used herein may contain polymericmaterial which is water-soluble when ion exchange sites are attachedthereto, all or a portion of which material may be extracted to formpores or channels in the beads. The preparation of such gel andextractable seed beads is described more fully hereinafter.

The copolymer beads are advantageously prepared by forming a crosslinkedfree radical containing matrix (hereinafter "free radical matrix"), andcontacting said free radical matrix with a monomer feed comprising atleast one monomer under conditions such that free radicals catalyze thepolymerization of said monomer to form copolymer beads having acore/shell structure. Said polymerization is carried out as a suspensionpolymerization wherein the polymeric matrix and the monomers to bepolymerized are suspended in a suitable suspending medium which isgenerally an aqueous solution containing a suspension stabilizer.

The preparation of the free radical matrix can be accomplished by anyconvenient procedure. Advantageously, said free radical matrix is of thein situ, single stage or second stage types as described hereinbelow.Said "in situ" type free radical matrix is advantageously formed bypolymerizing in suspension a monomeric mixture containing mono- andpolyethylenically unsaturated addition polymerizable monomers until theconversion of said monomers to polymers is at least 20, preferably atleast 50, more preferably between 50 and 80 percent. Said "single stage"free radical matrix is advantageously prepared by suspending a pluralityof seed particles in a continuous phase and swelling said seed particleswith a free radical initiator. Said "second stage" free radical matrixis advantageously prepared by suspending a plurality of seed particlesin a continuous phase, swelling said seed particles with an initialmonomer charge comprising mono- and polyethylenically unsaturatedmonomers and a free radical initiator and polymerizing the monomerswithin said seed particle until the conversion thereof to polymer is atleast 20, preferably 40 to .[.90.]. .Iadd.85.Iaddend., more preferablyabout 40 to about .[.95.]. .Iadd.90 .Iaddend.percent.

The "in situ" type free radical matrix is advantageously prepared by thesuspension polymerization of a monoethylenically unsaturated monomer anda polyethylenically unsaturated monomer to form a crosslinked matrix.The amount of polyethylenically unsaturated monomer employed is chosensuch that the seed particle is sufficiently crosslinked to render itinsoluble in the monomer feed but less than an amount which renders theseed unable to imbibe the monomers of the monomer feed. Generally, saidseed particle is prepared using from about 0.05 to about 12.5 weightpercent of crosslinking monomer. The polymerization is carried out usingfree radical initiators under conditions such that a multiplicity ofcrosslinked polymer particles is prepared. The polymerization iscontinued until the conversion of the monomers to polymer is at least20, preferably at least 50, more preferably about 50 to about 80percent. According to this process, crosslinked polymer particles areprepared containing therein a quantity of unreacted monomers and amultiplicity of free radicals.

In the preparation of the "single stage" free radical matrix, asuspension is formed comprising polymeric seed particles in a continuousphase. Said seed particles advantageously comprise a crosslinkedaddition polymer but may be a crosslinked condensation polymer such asphenol/formaldehyde polymer. Said seed particles are crosslinked in anamount which renders them insoluble in the type and amount of monomersemployed in later stages of the process but less than an amount whichrenders them unable to imbibe free radical initiators and monomers. Ingeneral, said seed particles are prepared using from about 0.05 to about12.5, preferably from about 0.2 to 2.0, weight percent of a crosslinkingmonomer. Into the suspension containing the crosslinked seed particlesis added a free radical initiator which is essentially insoluble in thecontinuous phase and which is imbibed by the seed particle. When thefree radical matrix is formed in this manner, the seed particle whichhas imbibed said free radical initiator comprises the "free radicalmatrix", as that term is employed herein.

Alternately and preferably, a "second stage" free radical matrix isemployed which is advantageously prepared by suspending a multiplicityof polymeric seed particles in an appropriate suspending medium,imbibing into said particles a free radical containing initial monomercharge and polymerizing the monomers in the initial monomer charge untilthe conversion thereof into polymer is at least about 20 to about.[.95.]. .Iadd.90 .Iaddend.percent, preferably at least 40 percent. Thissecond stage free radical matrix will then comprise two polymericnetworks. In this process, the seed is advantageously an additionpolymer but may be a condensation polymer such as a phenol/formaldehydepolymer. Said seed polymer may be crosslinked or noncrosslinked,provided that said seed particle is insoluble in the type and amount ofmonomers employed in the initial monomer charge. With the aforementionedbroad limits, the amount of crosslinking in the seed particles is chosensuch that the seed can imbibe the desired amount of monomers in theinitial monomer charge. In general, increased amounts of crosslinkingwill decrease the amount of the initial monomer charge which can beimbibed by the seed particles. Advantageously, the seed particles areprepared using less than about 10 weight percent of a crosslinkingmonomer, preferably from about 0.1 to about 1.0 weight percent of acrosslinking monomer.

The initial monomer charge employed in the preparation of the secondstage free radical matrix contains both mono- and polyethylenicallyunsaturated monomers which, when polymerized, form a crosslinkedpolymer. The amount of crosslinking monomer employed herein is generallysufficient to render the beads, when functionalized, insoluble in waterand to impart physical integrity and mechanical strength to the beads.In general, the initial monomer charge will comprise from about 0.5 toabout 25, preferably from about 1 to about 12, weight percent of acrosslinking monomer. In addition, said initial monomer charge willadvantageously comprise from about 0.005 to about 2 weight percent of afree radical initiator.

To reduce the amount of offsize particles or "fines" formed, therelative proportions of seed particles and initial monomer charge arechosen such that at least 75 weight percent, preferably essentially allof the initial monomer charge is imbibed into the seed particles. Saidproportions will, of course, vary with the size of the seed particlesand the degree of crosslinking in the seed particle. For example, a seedparticle of relatively small size will generally imbibe proportionatelyless monomer than larger particles of similar crosslink density.Similarly, high crosslink density in the seed particle limits theparticle's ability to imbibe monomers. In general, the seed particleswill generally imbibe from about 0.5 to about 19, preferably from about1.5 to about 9, times their weight of the initial monomer charge. Thefree radical matrix advantageously comprises from about 5, preferablyabout 10 and most preferably from about 25 to about 90, preferably toabout 70, more preferably to about 50, weight percent of the weight ofthe product copolymer bead.

The prepared free radical matrix is suspended in an appropriatesuspending medium. When single stage or second stage free radicalmatrices are employed, preparation of said matrices and the subsequentaddition and polymerization of the monomer feed are advantageously, andpreferably, carried out in a single reaction vessel. In general, saidsuspending medium is a liquid in which both the free radical matrix andthe monomers to be contacted therewith are insoluble. Said suspendingmedium is typically an aqueous solution containing from about 0.1 toabout 1.5 weight percent of a suspension stabilizer, but for thepolymerization of water-soluble monomers, may be an organic compound.Suitable suspension stabilizers include gelatin, polyvinyl alcohol,sodium methacrylate, carboxymethylmethylcellulose, as well assurfactants such as sodium lauryl sulfate, sulfonated polystyrenes andthe like. In addition, the suspension may suitably containpolymerization inhibitors dispersants, and other materials known to beadvantageously employed in the suspension polymerization ofethylenically unsaturated monomers.

The suspension is then contacted with a monomer feed comprising at leastone ethylenically unsaturated monomer under conditions such that thefree radicals contained in the free radical matrix catalyze thepolymerization of said monomer feed. Copolymer beads prepared accordingto this process usually exhibit a core/shell morphology. Generally, thefree radical matrix will reside mainly in the core of the polymer beadsprepared by this process, while the polymers formed from the monomerfeed will generally reside in the shell of the copolymer bead. However,it is believed that interpenetration occurs between the polymers of thefree radical matrix and those derived from the monomer feed.Accordingly, the interface between the core and shell may be gradualrather than sharp.

Advantageously, the suspension is heated to a temperature sufficient toinitiate the free radical polymerization of ethylenically unsaturatedmonomers. To the heated suspension is then added a monomer feed underconditions such that essentially all polymerization of said monomers isinitiated by the free radicals contained in the polymer matrix.Preferably, the ratio of the weight of polymer to the combined weight ofpolymer and monomer present at any time during the addition of themonomer feed (instantaneous conversion) is at least about 20, morepreferably at least 50 percent.

Instantaneous conversion may be measured in various ways, with theparticular means of monitoring the reaction left to the practitioner asa matter of choice. The reaction may be monitored chemically, such as bytaking periodic infrared spectra of the reaction mixture as the reactionproceeds to monitor the conversion of the carbon-carbon double bonds ofthe monomer to polymer. The difference in density between the unreactedmonomers and the polymers can also form a basis for monitoring themixture. For example, a reaction mixture containing about 1.35 g ofstyrene monomer per gram of water will have a density of about 0.936 gper cubic centimeter before polymerization and about 1.04 g afterpolymerization (at about 96 percent conversion). Said differences indensity can be monitored using gravimetric techniques or preferably bythe use of a nuclear densitometer such as an SG series density gaugesold by Texas Nuclear. More simply, the instantaneous conversion can bereadily calculated from the heat of polymerization.

The instantaneous conversion is advantageously controlled by adjustingthe rate at which the monomer feed is added to the suspension. Saidmonomer feed may be added continuously or intermittently to thesuspension at constant or various rates during the course of thepolymerization. Advantageously, the rate of addition of the monomer feedis such that the instantaneous conversion is at least 20, preferably atleast 50 percent at all times during the polymerization reaction.

The monomer feed may contain a proportion of a polyethylenicallyunsaturated monomer or may consist entirely of monoethylenicallyunsaturated monomers. It is noted here that the monomers in the monomerfeed may vary with time in the proportion of crosslinking monomercontained therein or in the type of monomers employed or both.Advantageously, the monomer feed will, on the average, contain aproportion of crosslinking monomers no greater than the averageproportion of crosslinking monomer in the polymeric matrix. Moreadvantageously, a lower proportion of the crosslinking monomer isemployed in the monomer feed, yielding a heterogeneous copolymer beadhaving a higher proportion of crosslinking in the core and a lowerproportion of crosslinking in the shell.

In order to ensure that the polymerization of the monomers in themonomer feed is essentially completely catalyzed by the free radicalscontained in the polymeric matrix, the monomer feed advantageouslycontains essentially no initiators. In addition, the continuous phase isalso essentially free of initiators. One or more free radical inhibitorswhich are soluble in the continuous phase are advantageously employed toinhibit the formation of free radicals in said continuous phase.Accordingly, while it is not intended that this invention be bound byany theory, it is believed that the generation of free radicals willoccur almost exclusively within the free radical polymer matrix, tendingto cause the monomers of the monomer feed to form high molecular weightchains which are highly entangled about the polymeric structure of thefree radical matrix.

After all the monomer feed is added to the reaction mixture, thereaction mixture is maintained at the polymerization temperature untilthe polymerization reaction is essentially complete. Advantageously, thepolymerization temperature is increased about 20°-30° C. during thefinal stages of the polymerization reaction to "finish off" thereaction. The resulting polymer beads are recovered via conventionalmeans such as filtration and advantageously dewatered and dried.

The monomers employed in the preparation of the free radical matrix(i.e., those employed in the formation of the seed particle and initialmonomer charge, if any) and the monomer feed are advantageouslysuspension polymerizable ethylenically unsaturated monomers. Suchsuspension polymerizable monomers are well known in the art andreference is made to Polymer Processes, edited by Calvin E.Schildknecht, published in 1956 by Interscience Publishers, Inc., NewYork, Chapter III, "Polymerization in Suspension" by E. Trommsdoff andC. E. Schildknecht, pp. 69-109 for purposes of illustration. In Table IIon pp. 78-81 of Schildknecht are listed diverse kinds of monomers whichcan be employed in the practice of this invention. Of such suspensionpolymerizable monomers, of particular interest herein are thewater-insoluble monomers including the monovinylidene aromatics such asstyrene, vinyl naphthalene, alkyl substituted styrenes (particularlymonoalkyl substituted styrenes such as vinyltoluene and ethylvinylbenzene) and halo-substituted styrenes such as bromo- orchlorostyrene, the polyvinylidene aromatic such as divinylbenzene,divinyltoluene, divinyl zylene, divinyl naphthalene, trivinylbenzene,divinyl diphenyl ether, divinyl diphenyl sulfone and the like, esters of.[.α,βethylenically.]. .Iadd.α,β -ethylenically .Iaddend.unsaturatedcarboxylic acids, particularly acrylic or methacrylic acid, such asmethyl methacrylate, ethyl acrylate, diverse alkylene diacrylates andalkylene dimethacrylates, and mixtures of one or more of said monomers.Of said monomers, the monovinylidene aromatics, particularly styrene ora mixture of styrene with a monoalkyl substituted styrene, thepolyvinylidene aromatics, particularly divinylbenzene, esters ofα,β-ethylenically unsaturated carboxylic acids, particularly methylmethacrylate of mixtures containing methylmethacrylate, particularly amixture of styrene and divinylbenzene or styrene, divinylbenzene andmethyl methacrylate are preferably employed herein.

Also included within the polymerizable monomers useful herein are thosemonomers which form a solution with a liquid, generally water, whereinthe resulting solution is sufficiently insoluble in one or more otherliquids, generally a water-immiscible oil or the like, such that themonomer solution forms droplets upon its dispersion in said otherliquid. Representative of such monomers are water-soluble monomers whichcan be polymerized using conventional water-in-oil suspension (i.e.inverse suspension) polymerization techniques such as described by U.S.Pat. No. 2,982,749, including ethylenically unsaturated carboxamidessuch as acrylamide, methacrylamide, aminoalkyl esters of unsaturatedcarboxylic acids and anhydrides, ethylenically unsaturated carboxylicacids, e.g. acrylic or methacrylic acid, and the like. Preferred of suchmonomers for use herein are the ethylenically unsaturated carboxamides,particularly acrylamide, and the ethylenically unsaturated carboxylicacids, particularly acrylic or methacrylic acid.

In addition to the aforementioned ethylenically unsaturated monomers,the seed particles employed in the preparation of the single stage andsecond stage free radical matrices can also comprise a crosslinkedcondensation polymer such as phenol/formaldehyde resin. In general, saidcondensation polymers must be able to imbibe the free radical initiatorsand the monomers of the initial monomer charge, if any, and the monomerfeed.

The monomer feed may contain different monomers than those used toprepare the free radical matrix. For example, the monomer feed maycomprise styrene, divinylbenzene and methylmethacrylate and the freeradical matrix may comprise primarily styrene/divinylbenzene polymers.When the free radical matrix is prepared by imbibing a catalystcontaining initial monomer charge into a seed particle, the seedparticle may contain different monomers than the initial monomer charge.Similarly, the composition of the polymers of the polymeric shell may bevaried from the inside to the outside of the shell by changing thecomposition of the monomer feed during the course of the polymerizationthereof. The polymers contained in the polymer beads used in thisinvention can be widely varied.

Beads having an extractable seed are advantageously prepared using ahighly crosslinked or noncrosslinked seed particle which is insoluble inthe amount and type of monomers used in the preparation of the polymericmatrix and the initial monomer charge, but when active ion exchangesites are attached thereto, become water-soluble and are extractablefrom the bead when immersed in water. Beads prepared having suchextractable seeds will contain small voids when all or a portion of theseed is removed therefrom.

Copolymer beads having relatively uniform size are prepared according tothe process of this invention by using uniform size seed particles.Uniform size seed particles are prepared by screening the seed particlesor by preparing the seed particles using a process which producespolymer particles of uniform size, such as those taught in publishedEuropean Patent Application Nos. 0005619 and 0051210. Advantageously, atleast 80 percent of the seed particles employed to prepare the copolymerbeads of this invention are greater than 0.5 and no more than 1.5 timesthe weight average particle size of the seed particles.

The size of the copolymer beads of this invention is advantageously inthe range from about 50 to 2000 microns, preferably from about 200 to1200 microns. Control of the size of the beads is achieved primarily bycontrolling the size and crosslinking in the seed particles employed, ifany, and the amount of monomers employed in the monomer feed. The seedparticles can range in size from very small particles, i.e. about 10microns, to larger particles having a diameter of 750 microns or more.Preferably the size of the seed particle is in the range from about 100to about 750 microns in diameter.

The polymer beads are converted to anion or cation exchange beads usingtechniques well known in the art for converting crosslinked additionpolymers of a mono- and polyethylenically unsaturated monomer to suchresins. In the preparation of weak base resins from poly(vinylaromatic)copolymer beads such as crosslinked polystyrene beads, the beads areadvantageously haloalkylated, preferably halomethylated, most preferablychloromethylated, and the ion active exchange groups subsequentlyattached to the haloalkylated copolymer. Methods for haloalkylating thecrosslinked addition copolymers and the haloalkylating agents includedin such methods are also well known in the art. Reference is madethereto for the purposes of this invention. Illustrative of such areU.S. Pat. Nos. 2,642,417; 2,960,480; 2,597,492; 2,597,493; 3,311,602 and2,616,817 and Ion Exchange by F. Helfferich, published in 1962 byMcGraw-Hill Book Company, N.Y. Typically, the haloalkylation reactionconsists of swelling the crosslinked addition copolymer with ahaloalkylating agent, preferably bromomethylmethyl ether,chloromethylmethyl ether or a mixture of formaldehyde and hydrochloricacid, most preferably chloromethylmethyl ether and then reacting thecopolymer and haloalkylating agent in the presence of a Friedel-Craftcatalyst such as zinc chloride, iron chloride and aluminum chloride.

Generally, ion exchange beads are prepared from the haloalkylated beadby contacting said bead with a compound reactive with the halogen of thehaloalkyl group and which, upon reaction, forms an active ion exchangegroup. Such compounds and methods for preparing ion exchange resinstherefrom, i.e., weak base resins and strong base resins, are well knownin the art and U.S. Pat. Nos. 2,632,000; 2,616,877; 2,642,417;2,632,001; 2,992,544, and F. Helfferich supra are illustrative thereof.Typically, a weak base resin is prepared by contacting the haloalkylatedcopolymer with ammonia, a primary amine or a secondary amine.Representative primary and secondary amines include the methyl amine,ethyl amine, butyl amine, cyclohexyl amine, dimethyl amine, diethylamine and the like. Strong base ion exchange resins are prepared usingtertiary amines such as trimethyl amine, triethyl amine, tributyl amine,dimethylisopropanol amine, ethylmethylpropyl amine or the like asaminating agents.

Amination generally comprises heating with reflux a mixture of thehaloalkylated copolymer beads and at least a stoichiometric amount ofthe aminating agent, i.e. ammonia or the amine, to a temperaturesufficient to react the aminating agent with the halogen atom attachedto the carbon atom in the alpha position to the aromatic nucleus of thepolymer. A swelling agent such as water, ethanol, methanol, methylenechloride, ethylene dichloride, dimethoxymethylene or combinationsthereof is optionally, but advantageously employed. Conventionally,amination is carried out at conditions such that anion exchange sitesare uniformly dispersed throughout the entire bead. Such completeamination is generally obtained within about 2 to about 24 hours atreaction temperature between 25° and about 150° C.

Methods for converting copolymer beads other than poly(vinyl-aromatic)beads to anion exchange resins are illustrated in Helfferich, supra, pp.48-58. In addition, methods for attaching other types of anion exchangegroups, such as phosphonium groups, to copolymer beads are describedtherein.

Cation exchange resin beads can be prepared using techniques well knownin the art for converting the crosslinked addition copolymer of mono-and polyethylenically unsaturated monomers to a cation exchange resin.Illustrative of such methods of preparing cation exchange resin are U.S.Pat. Nos. 3,266,007; 2,500,149; 2,631,127; 2,664,801; .[.2,764.566.]..Iadd.2,764,566 .Iaddend.and F. Helfferich, supra. In general, thecation exchange resins useful herein are strong acid resins which areprepared by sulfonating the copolymer beads. While the sulfonation maybe conducted neat, generally, the bead is swollen using any suitableswelling agent and the swollen bead is reacted with the sulfonatingagent such as sulfuric or chlorosulfonic acid or sulfur trioxide.Preferably, an excess amount of the sulfonating agent, for example, fromabout 2 to about 7 times the weight of the copolymer bead is employed.The sulfonation is conducted at a temperature from about 0° to about150° C.

Since the amount of crosslinker, e.g. DVB, employed in preparation ofthe core/shell structure beads varies as a function of the structureradius due to the techniques used to prepare the beads, a method toexpress crosslinking that reflects this fact will be employed. For theunfunctionalized copolymer beads, a toluene swelling test is useful todetermine the "effective" crosslink density as noted below in Example 1.For the functionalized resins, it is appropriate to use awater-absorption test in order to determine what is referred to inExamples 2 and 4 as "Apparent Relative Crosslink Percentage".

This value is derived by the comparison of the water absorptive capacityof a functionalized resin with the predetermined water absorptivecapacity of a set of standard gel-type resins made from the samecomonomers and of like functionality and equal capacity. To obtain thestandards by which the "Apparent Relative Crosslink" may be determinedin practical routine operations, a series of standard gel-type, e.g.styrene-DVB resins, are prepared having known DVB content, e.g. 4, 6, 8,10, 12 etc. percent. These resins are then given the desired functionalgroups, and a graph of the amounts of water absorbed, by the resin ateach level of DVB content, and for each functional group at variouscapacities, e.g. 3.0, 3.5, 4.0, 4.5, 5.0 etc. meq/g, is plotted fromexperimental findings.

By then comparing the measured water absorption capacity, normallyrecorded in weight percent water absorbed, of the shell/core resinshaving the same level of ion exchange capacity and of the samefunctionality, one may note the amount of DVB crosslinker in thestandard gel-type resin which exhibits the same level of waterabsorption as the core/shell ion exchange resin. The "Apparent RelativeCrosslink Percentage" is then reported as the weight percent of DVBcrosslinker that is present in the comparable standard resin.

In the present invention process, Component (1) and (2) resins suitablyhave "Apparent Relative Crosslink Percentages" of less than about 8percent, preferably less than or equal to about 7 percent and morepreferably less than or equal to about 6 percent, and more than about 3,preferably more than or equal to about 4 percent and most preferablymore than or equal to about 5 percent.

With regard to the operation of the invention process in the day to dayoperations of a BWR plant, no significant changes are required except tosubstitute the mixed bed ion exchanger described herein for ionexchangers presently employed for ion removal purposes.

When "breakthrough" occurs, the mixed bed exchanger may usually bereactivated several times by backwashing and agitation of the bed.However, because of the low level radioactivity of the captured ironions and particles, the bed is not normally regenerated in the sensecommonly used for ion exchangers, i.e. subjecting to strong acids andbases. Instead the resin with the captured irradiated species isnormally consolidated, collected and disposed of in the fashion of otherlow-level waste from nuclear power reactors.

The effluent from the bed may be monitored by standard means, such aslow level scintillation detection devices and analytical techniques foriron, to observe when breakthrough occurs and at that time the desiredsteps may be taken to reactivate the bed or collect and dispose of theused resin.

Because of the .[.resins,.]. .Iadd.resins' .Iaddend.exceptionaltoughness and resistance to crushing, the generation of resin "fines" iskept to a minimum, further enhancing the performance and life of theresin bed. Standard practices of screening the resins to remove anyfines generated in the shipping and handling of the resin particles, mayof course be employed when initially loading the apparatus, to maximizeperformance of the mixed bed ion exchanger.

The following examples are intended to illustrate the invention and arenot intended to limit the scope thereof in any way. All parts andpercentages are by weight unless otherwise noted.

EXAMPLE 1

Into a 3-liter, stainless steel reactor equipped with an agitator areloaded 35 parts by weight of 0.3 percent crosslinkedstyrene/divinylbenzene copolymer seed having a particle size of 150-300microns and sufficient water to suspend the seed particles. Furtheradded, with agitation, is an initial monomer charge comprising 1.9 partsdivinylbenzene (DVB), 63 parts styrene, 0.036 part t-butylperoctoate(TBPO) (based on the total weight of all monomers employed), 0.025 partt-butylperbenzoate (TBPB), (based on the total weight of all monomersemployed), 0.15 part carboxymethyl methylcellulose (CMMC) and 0.15 partsodium dichromate. Water is then added in an amount such that the weightratio of aqueous to organic phase is 1.0 after the addition of themonomer feed. The reaction mixture is then heated to 70° C. andmaintained at 70° C. for 3 hours, at which time a monomer feed of 98.5percent of styrene and 1.5 percent of DVB is begun. The monomer feed isfed at a constant rate into the reactor over a 10-hour period until saidmonomer feed comprises 71.4 percent by weight of the combined weight ofthe initial charge and the monomer feed. The reaction mixture is heatedat 90° C. for an additional 1.5 hours and then raised to 100° C. forapproximately 1.5 hours.

A portion of the copolymer beads thus obtained is dried and a 20-mlportion is measured into a column. The beads are then immersed intoluene and the change in volume of the beads is measured. From thechange in volume, the effective crosslink density is determined using agraph such as depicted on page 879 of the "Kirk-Othmer Encyclopedia ofChemical Technology", 2nd Ed., published in 1966 by John Wiley and Sons,Vol. II, R. M. Wheaton and A. H. Seamster, "Ion Exchange".

A 100-g portion of the copolymer beads is chloromethylated by reactingthe beads with an excess of chloromethylmethyl ether in the presence offerric chloride. The chloromethylated beads are then reacted withtrimethylamine to form a strong base anion exchange resin bearing aplurality of quaternary ammonium ions. The anion exchange resin is thentested for percent original spheres, crush strength, resin size, osmoticshock resistance, dry weight capacity, and water retention capacity.

The crush strength of the anion exchange resin of this and the followingexamples is determine by testing about 30 beads using a ChatillionScale, Model DPP-1 KG. The force, in grams, required to fracture eachindividual bead is recorded, with the crush strength reported as theaverage of about 30 such testings.

The number percent of the resin beads having flawless spheres (i.e.,"percent original perfect spheres"), is evaluated by placing a smallamount of the resin in a petri dish. A microscope having a cameramounted thereon is adjusted until about 200 resin beads fall within thevision field of the camera. A photograph is then taken. From thephotograph, the total number of beads are counted, the total number ofbroken or cracked are counted, and the number percent of spherical beadscalculated.

The size of the resin beads, when swollen with water, is determined byscreen analysis.

The resistance of the resin beads to osmotic shock is tested using theprocedure described hereinbefore wherein the beads are contacted with 10cycles of alternating 8M hydrochloric and 8M NaOH, with the resultsreported as the number percent of beads which remain unbroken after 10cycles of the test, using microphoto graphic counting techniquedescribed above.

The dry weight capacity of the resin is determined by drying a sample ofthe resin in the chloride form under an infrared lamp on a moisturebalance until a constant weight is obtained. The dried resin is thencooled to room temperature in a closed vessel. About 0.5 gram of thedried resin is weighed into a suitable flask. The resin is then heatedto 70°-80° C. with 100 ml of distilled water, 4 ml of sulfuric acid and5 g Na₂ SO₄ for 5 minutes. The mixture is cooled and titrated with 0.1NAgNO₃ to an endpoint as indicated using a chloride sensitive electrode.The dry weight capacity is then reported as meq/g of resin. Theproperties of the resin so prepared are as follows:

Percent Original Perfect Spheres: 98

Average Crush Strength: 1470 g/bead

Resin Bead Size: 600-1000 microns

Percent Unbroken (Osmotic Shock Test--10 cycles): 80

Dry Weight Capacity: 4.28 meq/g

Toluene Swell Effective Crosslink Density: 4

Average DVB Percentage: 1.64

(Percent of DVB used in preparation of copolymer beads calculated basedon total weight of seeds and all monomer fed)

EXAMPLE 2

In a fashion similar to the method described in Example 1, copolymerbeads are prepared as follows:

Into a sealed stainless steel reactor equipped with an agitator areloaded 100 parts water and 100 parts of a styrene-DVB (0.3% DBV)copolymer as seeds which have a very uniform average particle size of350-360 microns. The mixture is mechanically agitated. To the reactor isadded 124.7 parts of monomer mixture consisting of 87.1% styrene, 12.4%of a 56% solution DVB, 0.18% TBPO and 0.14% TBPB and the resultingmixture is agitated for one hour at 30° C. to fully imbibe the monomermixture in the seed particles.

Then is added to the reactor 127.8 parts of suspending agent consistingof 97.8% water, 1.7% gelatin and 0.5% (30% active) sodium lauryl sulfateand the pressure in the reactor is reduced to avoid explosiveair/monomer mixtures. The contents of the reactor are then heated to 78°C. and held at that temperature for two hours.

A second monomer feed consisting of 96.4 parts styrene and 2 parts of(3.6 parts of a 56% active solution) DVB is then pumped into the reactorover four hours at a rate of 1 part per minute, until 240 parts of thesecond monomer feed have been added. The contents of the reactor areheld at 78° C. for three hours more, then raised to 110° C. and held atthat temperature for two additional hours to complete polymerization ofthe monomers.

The reactor contents are cooled to under 40° C. and the resulting beadsare then washed with water to remove the suspending agent and are dried.

EXAMPLE 2A

In the manner described in Example 1, a portion of copolymer beadsprepared by the method described in Example 2 are converted to strongbase anion resins by a standard means of functionalizing withchloromethyl methyl ether and trimethyl amine. The resulting anionexchange resin beads have the following properties, in chloride form:

    ______________________________________                                        Average Crush Strength:  460    g/bead                                        Resin Bead Size (±10 percent):                                                                      550    microns                                       Percent Unbroken (Osmotic Shock Test -                                                                 95                                                   10 cycles):                                                                   Apparent Relative Swell Crosslink Percentage:                                                          6                                                    Dry Weight Capacity:     3.9    meq/g                                         ______________________________________                                    

EXAMPLE 2B

A portion of copolymer beads prepared by the method described in Example2 are converted to strong acid cation resins by standard means ofsulfonation in a glass lined reactor in the following manner:

To the reactor 464 parts of 99 percent sulfuric acid are added and tothis, 100 parts of the copolymer beads are added slowly with mechanicalagitation. Also with mechanical agitation, a chlorinated solvent, 17parts, is added to swell the beads.

The reactor contents are then gradually heated to 115° C. and maintainedat that level for two hours after which they are permitted to cool. Theyare then treated with portions of aqueous sulfuric acid of decreasingconcentration until the beads are fully hydrated. The resin beads areconverted to the sodium form by slurring in aqueous 2 molar sodiumhydroxide and washed with water to remove salt and excess caustic.

In the sodium form, the resulting cation exchange resin beads have thefollowing properties:

    ______________________________________                                        Average Crush Strength:  680    g/bead                                        Resin Bead Size (±10 percent):                                                                      580    microns                                       Percent Unbroken (Osmotic Shock Test -                                                                 98                                                   10 cycles):                                                                   Apparent Relative Swell Crosslink Percentage:                                                          6                                                    Dry Weight Capacity:     4.8    meq/g                                         ______________________________________                                    

EXAMPLE 3

The resin beads of example 2A .[.are,.]. .Iadd.are .Iaddend.converted toabout 93 percent hydroxyl form by chromatographically first convertingthem to carbonate form with sodium carbonate solution and then to the.[.hydroxy.]. .Iadd.hydroxyl .Iaddend.form with an excess of 1 molarsodium hydroxide and then washing repeatedly with water. The resin beadsof example 2B are converted to about 98 percent hydrogen (.Iadd.acid)form by slurrying them in an excess of 1 molar sulfuric .Iaddend.acidand then washing repeatedly in water to remove any excess acid and anysalt formed.

Then aqueous slurries of each resin are combined in a ratio of 1 partthe anion exchange resin to 2 parts of the cation exchange resin (partsby volume, wet) in a vessel of suitable size and then mechanically mixedby air sparging to obtain a bed in which the two species are distributedrelatively uniformly throughout. This uniform mixture is then loadedcarefully into an upright column of sufficient diameter to handle thecondensate flow rate in a BWR. The column, mounted securely, is thenconnected into the condensate flow stream by suitable valving. Thecondensate influent to the column has an iron content of about 20 partsper billion (ppb). In runs with two such columns, the effluent from thecolumns has an iron content at day 1 initially of between 1.0 and 1.5ppb, falling to between 0.5 and 0.6 ppb on day 2 and remaining after 15days in operation, at between 0.3 and 0.9 ppb.

.Iadd.COMPARISON .Iaddend.EXAMPLE 4

In the same fashion as Example 3, a mixed bed is prepared fromcommercial gel-type anion and cation exchange resins having thefollowing characteristics:

    ______________________________________                                        Anion Exchange Resin                                                          Average Crush Strength:                                                                             390      g/bead                                         Bead Size Range:      300-1200 microns                                        Percent Unbroken (Osmotic Shock                                                                     45                                                      Test - 10 cycles):                                                            Apparent Relative Crosslink Percentage:                                                             8                                                       Dry Weight Capacity:  2.9      meq/g                                          Cation Exchange Resin                                                         Average Crush Strength:                                                                             680      g/bead                                         Bead Size Range:      300-1200 microns                                        Percent Unbroken Osmotic Shock                                                                      45                                                      Test - 10 cycles):                                                            Apparent Relative Crosslink Percentage:                                                             8                                                       Dry Weight Capacity:  4.8      meq/g                                          ______________________________________                                    

A mixed bed of these two Anion and Cation resins in essentially the sameratio as for the Example 3 resins, is prepared, loaded in a column andfed the same condensate influent stream (20 ppb iron) as in Example 3.The initial effluent from mixed bed is at day 1 about 0.5 ppb, at about0.5 ppb on day 2 and then rising steadily thereafter to reach about 5ppb on day 5 and remaining at about 4.5 ppb iron on day 15.

I claim:
 1. A process for treatment of power plant condensate waterwhich contains colloidal iron, comprising:(a) contacting the condensatewater with a mixed bed ion exchanger and (b) thereafter removing thewater with reduced colloidal iron content from contact with the ionexchanger,wherein the mixed bed ion exchanger consists essentially of:Component (1)--a particulate cation exchange resin bead, at least aportion of which is in the acid form, and Component (2)--a particulateanion exchange resin bead,and wherein at least the Component (1) resin,prior to functionalization, primarily comprises gel-type copolymer beadshaving core and shell structure, which beads have been produced instages by first forming in a continuous phase a multiplicity of polymermatrices which contain free radicals, then imbibing in said matrices amonomer feed comprising at least one monomer but no free radicalinitiator and subjecting the imbibed monomer feed to conditions suchthat the free radicals in the matrices catalyze polymerization of themonomer feed within the matrices.
 2. The process of claim 1 whereinComponent (2) resin, prior to functionalization, primarily comprisesgel-type copolymer beads, having core and shell structure, which havebeen produced in stages by first forming in a continuous phase amultiplicity of polymer matrices which contain free radicals, thenimbibing in said matrices a monomer feed comprising at least one monomerbut no free radical initiator and subjecting the imbibed monomer feed toconditions such that the free radicals in the matrices catalyzepolymerization of the monomer feed within the matrices.
 3. The processof claim 1 or 2 wherein the copolymer beads comprise beads of copolymersprepared from a vinylidene aromatic monomer and a divinylidene aromaticmonomer.
 4. The process of claim 1 wherein the copolymer beads comprisebeads of copolymers prepared from styrene and divinylbenzene.
 5. Theprocess of claim 2 wherein the copolymer beads of Component (1) andComponent (2) resins both comprise copolymer beads prepared from styreneand divinylbenzene.
 6. The process of claim 4 or 5 wherein thefunctionalized copolymer beads of Components (1) and (2) have crushstrengths of at least about 500 g/bead and 400 g/bead respectively. 7.The process of claim 4 or 5 wherein the functionalized copolymer beadsof Components (1) and (2) have osmotic shock resistance such that lessthan 15 percent by number of the beads are broken after contact with 10cycles of alternating 8 molar hydrochloric acid and 8 molar sodiumhydroxide.
 8. The process of claim 1 or 2 wherein the gel-type copolymerbeads are prepared by:(i) suspending a multiplicity ofstyrene--divinylbenzene copolymer seed particles, of from about 0.1 toabout 1.0 percent divinylbenzene by weight, in a continuous aqueousphase, (ii) imbibing in said seed particles a monomer mixture of styreneand divinylbenzene and free radical initiator and then initiating thereaction of the imbibed styrene and divinylbenzene until about 40 to.[.95.]. .Iadd.90 .Iaddend.weight percent of said monomers are convertedto polymer in the particles, then, (iii) continuing to add to theaqueous suspension a second monomer composition, comprising styrene andessentially no free radical initiator, under conditions that the secondmonomer composition is imbibed in the particles and the polymerizationof the second monomer composition is catalyzed within said particles. 9.A process of claim 8 wherein stage (ii) the first monomer mixturecomprises about 1 to about .[.12.]. .Iadd.10 .Iaddend.percent by weight.[.dinvinylbenzene.]. .Iadd.divinylbenzene.Iaddend..
 10. The process ofclaim 8 wherein stage (iii) the second monomer composition comprisesabout 95 to about 100 percent styrene.
 11. The process of claim 1wherein Component (1), prior to contact with the condensate water, hasbeen converted primarily to the acid form.
 12. The process of claim 1 or2 wherein Component (2), prior to contact with the condensate water, hasbeen converted primarily to the hydroxyl form.
 13. The process of claim1 or 2 wherein the volume ratio of component (1):Component (2) isbetween about 2:1 and about 1:1.
 14. The process of claim 1 wherein thegel-type copolymer beads have an average diameter size of from 200 to1200 microns.